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    <script>
        /* 函数传不定参
           函数内部有一个arguments对象，接收函数传递过来的参数
           是一个类似数组的对象
        */  
        function go(a,b,c){
            console.log(a)
            console.log(a+b)
            console.log(a+b+c)
            console.log(arguments)
        }  
        /* go(10)   //10  NaN  NaN */
        /* go()   //undifined  NaN NaN  */
        go(10,20,30,40)   //10  30  60
    </script>
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